Current methods for identifying a song in a database are based on feature extraction and matching. U.S. Pat. No. 5,918,223 discloses feature extraction techniques for content analysis in order to retrieve songs based on similarity. U.S. Pat. No. 6,201,176 similarly discloses feature extraction used for retrieving songs based on minimum feature distance. In another method, features, such as loudness, melody, pitch and tempo, may be extracted from a hummed song, for example, and decision rules are applied to retrieve probable matches from a database of songs. However, it is difficult to derive reliable features from music samples. Additionally, feature matching is sensitive to the distortions of imperfect acquisition, such as improper humming, and also to noise in microphone-recorded music samples. Therefore, feature matching has not resulted in reliable searches from recorded samples.
Other methods for identifying a song in a database do not involve processing audio data. For example, one method involves the use of a small appliance that is capable of recording the time of day. The appliance is activated when the user is interested in a song that is currently playing on the radio. The appliance is coupled to a computer system that is given access to a website operated by a service. The user transmits the recorded time to the website using the appliance and provides additional information related to location and the identity of the radio station which played the song. This information is received by the website together with play list timing information from the radio station identified. The recorded time is cross-referenced against the play list timing information. The name of the song and the artist are then provided to the user by the service through the website. Unfortunately, this method requires that the user remember the identity of the radio station that played the song when the appliance was activated. Additionally, the radio station must subscribe to the service and possess the supporting infrastructure necessary to participate in the service. Furthermore, the method is only effective for identifying music played on the radio, and not in other contexts, such as cinema presentations.